JP2014201289A - Driving control device for hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a driving control device for a hybrid vehicle capable of avoiding motor lock of a motor even when driving wheels become a rotation stop state when a driving force is required by a driver.SOLUTION: In a rotation stop state of a motor MG, that is, when motor lock occurs and it is determined, a lock-up clutch L/C is made to be in a released or a slip state. Therefore, the situation is solved in which a large current continuously flows in a coil of a specified phase of the motor MG and in a current control element of a specified phase of an inverter 54, and the coil of the specified phase of the motor MG and the current control element of the specified phase of the inverter 54 can be suitably prevented from being thermally damaged. At the same time, as a torque amplifying action of a torque converter 16 can be acquired, there is an advantage of increase in a transmission torque to driving wheels.

Description

  The present invention relates to a drive control device for a hybrid vehicle including an engine and an electric motor as driving power sources for traveling, and particularly protects the electric motor when the motor is locked when the electric motor is composed of a permanent magnet type motor. It is about technology.

  2. Description of the Related Art Hybrid vehicles including a fluid transmission device with a lock-up clutch and a transmission between an engine and an electric motor used as a driving source and driving wheels of the vehicle are well known. An electric motor used in such a hybrid vehicle is composed of a permanent magnet type electric motor, for example, a permanent magnet type AC synchronous motor (Interior Permanent Magnet Synchronous Motor: IPM), and is driven by a multiphase AC driving current output from an inverter. It is like that.

  In the hybrid vehicle described above, for example, when the driving wheel is fitted into a depression or a side groove on the road surface and the driving wheel to which the driving force is transmitted stops or rotates slightly, or to the curb If the driving force and the thrust in the downward direction due to the vehicle weight are balanced when the vehicle is on the road or when the hill is stopped, the driving wheel and the motor are mechanically connected via an axle or gear train. Even if a driving force is requested by operation, the rotor of the electric motor may be in a rotation stopped state. Such a state of the electric motor is called a motor lock. If such a motor lock state continues, a relatively large current continues to flow through the current control element of the specific phase of the motor or the specific phase of the inverter. The phase current control element could be thermally damaged.

  In this regard, in the vehicle drive motor control device described in Patent Document 1, when the motor lock occurs, the motor drive current is reduced until the rotor returns, and then the motor drive lock is repeatedly performed. When the motor lock is not resolved, the control is disclosed to protect the coil of the specific phase of the motor and the current control element of the specific phase of the inverter from thermal damage by reducing the current to such an extent that the motor can be continuously energized. ing. However, in this conventional hybrid vehicle drive control device, the drive current to the electric motor is reduced, so there is a risk that the vehicle will slide down on, for example, an uphill road.

JP 2010-011546 A JP 2010-111193 A

  On the other hand, the hybrid vehicle described in Patent Document 2 is configured by sequentially connecting an engine, a first clutch, an electric motor, a second clutch, and a transmission. In the control device, when a motor lock occurs, By reducing the torque of the motor and increasing the output torque of the engine with the two clutches in the slip state, the motor is protected from heat without reducing the driving force of the vehicle. According to this, the heat protection of the electric motor is performed and the occurrence of the vehicle slipping on the uphill road is eliminated.

  However, if the second clutch cannot be slipped any more from the viewpoint of thermal protection due to the temperature rise of the slipped second clutch, the engine cannot be rotated and it is necessary to maintain the driving force by the electric motor. As a result, the motor could not be thermally protected. There is also a problem that the power performance of the vehicle is lowered due to the temperature rise of the electric motor.

  The present invention has been made against the background of the above circumstances. The first object of the present invention is that even when the driving wheel is stopped when the driving force is requested by the driver. An object of the present invention is to provide a drive control device for a hybrid vehicle that can protect the electric motor with heat. The second object is to provide a hybrid that can suppress a decrease in the power performance of the vehicle due to a rise in the temperature of the motor when the driving wheels are in a rotation stop state when the driving force is requested by the driver. The object is to provide a drive control device for a vehicle.

  The gist of the first invention for achieving the first object is as follows: (a) a hybrid equipped with an engine as a drive source, a fluid transmission device with a lockup clutch and a transmission between a motor and a drive wheel; A drive control apparatus for a vehicle, wherein (b) a rotation stop state of the motor is determined based on at least a rotation speed of the motor and a driving force of the motor, and (c) a rotation stop state of the motor is determined. The lock-up clutch is released or slipped.

  In this way, when the rotation stop state of the electric motor occurs and it is determined, the lockup clutch is released or slipped, thereby allowing relative rotation between the input side and the output side of the torque converter. Therefore, the rotation stop state of the electric motor is avoided. Therefore, since it is eliminated that a large current continues to flow in the specific phase coil of the motor or the specific phase current control element of the inverter, the specific phase coil of the motor or the specific phase current control element of the inverter Prevents thermal damage.

  Preferably, when the rotation stop state of the electric motor is determined, and the coil temperature of the electric motor or the temperature of the inverter that controls the electric current of the electric motor is equal to or higher than a preset high temperature determination value, the lockup clutch Is released or slipped. In this way, the lock-up clutch is released or slipped only when the coil temperature of the motor or the temperature of the inverter that controls the current of the motor exceeds a preset high temperature judgment value. When the vehicle is running, the lockup clutch is engaged as much as possible, and the transmission efficiency of the driving force of the hybrid vehicle is increased.

  Preferably, the slip amount of the lock-up clutch is increased as the coil temperature of the electric motor or the temperature of the inverter that controls the electric current of the electric motor is higher than when the temperature is lower. The higher the coil temperature of the electric motor or the temperature of the inverter that controls the electric current of the electric motor is, the more it is necessary to avoid the motor lock state. Thus, the heat protection of the electric motor can be appropriately obtained.

  Preferably, the rotation stop state of the electric motor is determined when the accelerator opening or the required driving force based on the accelerator opening is equal to or greater than a predetermined value and the rotation speed or the vehicle speed of the electric motor is equal to or smaller than a predetermined value. If it does in this way, the motor lock of the electric motor accompanying the rotation stop state of the drive wheel which needs thermal protection will be judged correctly.

  The gist of the second invention for achieving the second object is as follows: (a) an engine as a drive source, a fluid transmission device with a lock-up clutch between the motor and the drive wheel, and a transmission; The electric motor is a drive control device for a hybrid vehicle that is a permanent magnet type AC synchronous motor that is rotationally driven by an alternating current controlled by an inverter, and (b) the coil temperature of the electric motor or the temperature of the inverter is preset. When the temperature reaches or exceeds the determined temperature, the lockup clutch is released or slipped. In this way, the lockup clutch is released or slipped when the coil temperature of the motor or the temperature of the inverter becomes equal to or higher than a preset judgment temperature, so that the torque converter can be switched between the input side and the output side. Relative rotation is allowed and the electric motor is rotated. Therefore, the temperature of the electric motor is lowered, and a reduction in the power performance of the vehicle due to the temperature rise of the electric motor can be suppressed.

  Preferably, the slip amount of the lock-up clutch is increased as the coil temperature of the electric motor or the temperature of the inverter that controls the electric current of the electric motor is higher than when the temperature is lower. As described above, since the electric motor is rotated as the temperature is higher, the deterioration of the power performance of the vehicle due to the temperature rise of the electric motor is more appropriately suppressed.

It is a figure explaining the schematic structure of the hybrid vehicle to which this invention is applied, and is a figure explaining the principal part of the control system in a vehicle. It is a functional block diagram explaining the principal part of the control function of an electronic controller. It is a figure explaining the relationship memorize | stored previously used by the lockup clutch control part of FIG. It is a flowchart explaining the main part of the control operation of the electronic control unit, that is, the control for appropriately performing the heat protection of the motor when the motor lock occurs.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram illustrating a schematic configuration of a hybrid vehicle 10 to which the present invention is applied, and a diagram illustrating a main part of a control system for various controls in the vehicle 10. In FIG. 1, a hybrid vehicle 10 is a hybrid vehicle including a power transmission device 12, an engine 14 that functions as a driving force source for traveling, and an electric motor MG. The power transmission device 12 includes an engine connection / disconnection clutch K0 (hereinafter referred to as connection / disconnection clutch K0) and a torque converter with a lockup clutch L / C in order from the engine 14 side in a transmission case 20 as a non-rotating member. 16 and an automatic transmission 18 or the like. The power transmission device 12 is connected to a propeller shaft 26 connected to a transmission output shaft 24 that is an output rotating member of the automatic transmission 18, a differential gear 28 connected to the propeller shaft 26, and the differential gear 28. And a pair of axles 30 and the like. The power transmission device 12 configured in this manner is suitably used for, for example, an FR (front engine / rear drive) type vehicle 10. In the power transmission device 12, the power of the engine 14 (also synonymous with torque and force unless otherwise distinguished) connects the crankshaft of the engine 14 and the connection / disconnection clutch K0 when the connection / disconnection clutch K0 is engaged. It is transmitted from the engine connecting shaft 32 to the pair of drive wheels 34 via the connecting / disconnecting clutch K0, the torque converter 16, the automatic transmission 18, the propeller shaft 26, the differential gear 28, the pair of axles 30, and the like in order. The electric motor MG is connected to a power transmission path between the connection / disconnection clutch K0 and the torque converter 16 in the transmission case 20, and the power of the electric motor MG is sequentially passed through the torque converter 16, the automatic transmission 18 and the like. It is transmitted to the drive wheel 34. Thus, the power transmission device 12 constitutes a power transmission path from the engine 14 to the drive wheels 34.

  The torque converter 16 is a fluid transmission device that outputs the power input to the pump impeller 16a through the fluid to output from the turbine impeller 16b. The pump impeller 16a is connected to the engine connecting shaft 32 via the connection / disconnection clutch K0 and is directly connected to the electric motor MG. The turbine impeller 16 b is directly connected to a transmission input shaft 36 that is an input rotation member of the automatic transmission 18. An oil pump 22 is connected to the pump impeller 16a. The oil pump 22 is rotationally driven by the engine 14 (and / or the electric motor MG) to generate hydraulic pressure for executing the shift control of the automatic transmission 18 and the engagement / release control of the connection / disconnection clutch K0. It is a mechanical oil pump.

  The automatic transmission 18 constitutes a part of a power transmission path between the engine 14 and the electric motor MG and the drive wheels 34, and the power from the driving power source for travel (the engine 14 and the electric motor MG) is directed to the drive wheels 34. A transmission for transmission. The automatic transmission 18 is a known planet in which a plurality of shift stages (gear stages) having different gear ratios (gear ratios) γ (= transmission input rotation speed Nin / transmission output rotation speed Nout) are selectively established. A gear type multi-stage transmission or a known continuously variable transmission whose gear ratio γ is continuously changed continuously. The automatic transmission 18 includes a plurality of friction engagement devices that selectively establish a plurality of gear stages by controlling, for example, a hydraulic actuator by a hydraulic control circuit 40. By selectively engaging the two, a predetermined gear stage (gear ratio) corresponding to the driver's accelerator operation, vehicle speed V, or the like is established. When the vehicle is operated to the parking position or the neutral position, all the friction engagement devices are released, so that the power transmission path in the automatic transmission 18 is released. In FIG. 1, the plurality of friction engagement devices are representatively shown as the clutch CL.

  The electric motor MG is a so-called motor generator that functions as a drive source and also has a function as a motor that generates mechanical power from electric energy and a function as a generator that generates electric energy from mechanical energy. The electric motor MG is composed of a permanent magnet type motor (IPM), for example, a three-phase permanent magnet type synchronous motor (IPM) in which a plurality of magnetic poles are formed in a rotor by magnetization and a stator forms a rotating magnetic field. Has been. For this reason, for example, when the driving wheel is fitted into a recess or a side groove on the road surface and the driving wheel to which the driving force is transmitted stops or rotates slightly, or the driving wheel is turned to the curb When the motor lock that causes the motor MG to stop rotating when the driving force is balanced with the thrust in the downward direction due to the vehicle weight when riding or when the hill is stopped is stopped Since a relatively large current continues to flow through the specific phase coil of the MG and the specific phase current control element of the inverter, the specific phase coil of the motor MG and the specific phase current control element of the inverter are thermally damaged. There was a possibility of receiving.

  The electric motor MG is connected to the battery unit 52 via a power supply control unit (PCU) 50. The electric motor MG functions as a driving force source for traveling that generates traveling power together with the engine 14 as an alternative to the engine 14 that is a power source. The electric motor MG generates electric energy by regeneration from the power generated by the engine 14 and the driven force input from the drive wheel 34 side, and stores the electric energy in the battery unit 52 via the power control unit 50. And so on. The electric motor MG is operatively connected to the pump impeller 16a, and power is transmitted between the electric motor MG and the pump impeller 16a. Therefore, the electric motor MG is connected to the transmission input shaft 36 of the automatic transmission 18 so as to be able to transmit power without the connection / disconnection clutch K0.

  The starter motor SM has a pinion that meshes with a ring gear provided on the crankshaft 32 of the engine 14 on the output shaft, and rotationally drives the engine 14 when the engine 14 is started. Further, a part of the output torque of the engine 14 is converted into electric energy.

  The connection / disconnection clutch K0 is a wet multi-plate hydraulic friction engagement device in which, for example, a plurality of friction plates stacked on each other are pressed by a hydraulic actuator, and hydraulic control is performed using the hydraulic pressure generated by the oil pump 22 as a source pressure. Engagement release control is performed by the circuit 40. In the engagement release control, the torque capacity (hereinafter referred to as K0 torque) of the connection / disconnection clutch K0 is changed by adjusting the pressure of a linear solenoid valve or the like in the hydraulic control circuit 40, for example. In the engaged state of the connection / disconnection clutch K0, the pump impeller 16a and the engine 14 are integrally rotated via the engine connecting shaft 32. Therefore, the engine 14 and the electric motor MG are indirectly connected via the connection / disconnection clutch K0 without differential relative rotation. On the other hand, in the released state of the connection / disconnection clutch K0, power transmission between the engine 14 and the pump impeller 16a is interrupted. That is, the engine 14 and the drive wheel 34 are disconnected by releasing the connection / disconnection clutch K0. Since the electric motor MG is connected to the pump impeller 16a, the connection / disconnection clutch K0 is provided in a power transmission path between the engine 14 and the electric motor MG, and also functions as a clutch for connecting / disconnecting the power transmission path.

  The power control unit 50 is a comparison between the inverter unit 54 that controls transmission and reception of electric power related to the operation of the electric motor MG, the boost converter unit 56 disposed between the battery unit 52 and the inverter unit 54, and the battery unit 52 side. DC / DC converter 60 that charges auxiliary battery 58 by stepping down the target high voltage to a low voltage of about 12V to 24V, and relay DR that controls electric motor SM for starting by supplying electric power of auxiliary battery 58 And an input capacitor (or filter capacitor) Ci provided between terminals of the boost converter unit 56 on the battery unit 52 side.

  The inverter unit 54 includes, for example, a known switching element, and in response to a command from an electronic control device 90 (particularly, MG_ECU), which will be described later, to obtain the output torque or regenerative torque required for the electric motor MG. The switching operation of the switching element is controlled. Boost converter unit 56 functions as a reactor L, an upper arm 62 (switching element Q1 and diode D1), a lower arm 64 (switching element Q2 and diode D2), and a power storage member that temporarily stores electric power related to the operation of electric motor MG. A smoothing capacitor Cs and a discharge resistor Rd provided in parallel with the smoothing capacitor Cs are provided. The discharge resistor Rd has a sufficiently large resistance value. For example, when the ignition is off, the charge stored in the smoothing capacitor Cs is slowly discharged.

  The battery unit 52 includes, for example, a battery unit 68 that is a chargeable / dischargeable secondary battery such as a lithium ion assembled battery or a nickel hydride assembled battery, and a power control unit according to a command from an electronic control device 90 (particularly, HV_ECU) described later. 50, system relays SR1 and SR2 that open and close an electrical path to and from the power control unit 50 (that is, connect and disconnect the battery unit 68 to and from the power control unit 50). The battery unit 68 may be, for example, a capacitor or a capacitor.

  The hybrid vehicle 10 is provided with an electronic control unit 90 including a control unit for the vehicle 10 related to control of the entire vehicle, for example. The electronic control unit 90 includes, for example, a so-called microcomputer having a CPU, a RAM, a ROM, an input / output interface, and the like. The CPU uses a temporary storage function of the RAM and follows a program stored in the ROM in advance. Various controls of the vehicle 10 are executed by performing signal processing. For example, the electronic control unit 90 performs output control of the engine 14, drive control of the motor MG including regeneration control of the motor MG, shift control of the automatic transmission 18, torque capacity control of the connection / disconnection clutch K0, and the like. The computer is divided into a hybrid control computer (HV_ECU), an electric motor control computer (MG_ECU), a shift control computer (AT_ECU), and the like that control the entire vehicle as necessary. The electronic control unit 90 includes various sensors (for example, an engine rotational speed sensor 70, a turbine rotational speed sensor 72, an output shaft rotational speed sensor 74, an electric motor rotational speed sensor 76, an accelerator opening sensor 78, an acceleration sensor 80, a battery sensor 82, Various signals (for example, the engine rotational speed Ne, which is the rotational speed of the engine 14, the turbine rotational speed Nt, that is, the transmission input shaft 36) based on values detected by the motor coil temperature sensor 84, the inverter temperature sensor 86, the lever position sensor 88, and the like. The transmission input rotational speed Nin which is the rotational speed of the transmission, the transmission output rotational speed Nout which is the rotational speed of the transmission output shaft 24 corresponding to the vehicle speed V, the motor rotational speed Nmg which is the rotational speed of the motor MG, the vehicle by the driver The accelerator opening θacc corresponding to the required drive amount for 10 and the acceleration acting on the vehicle 10 (Or deceleration) G, state of charge (charge capacity) SOC of battery unit 68, rotation phase θ of electric motor MG, coil temperature Tmc of electric motor MG, temperature Ti of inverter 54, position Ps of shift lever 89, etc.) Is done. From the electronic control unit 90, various command signals (for example, an engine control command signal Se, an electric motor) are provided to each device (for example, the engine 14, the inverter unit 54, the hydraulic control circuit 40, the battery unit 52, the relay DR, etc.) provided in the vehicle 10. Control command signal Sm, hydraulic control command signal Sp, power control command signal Sbat, start signal Sss, etc.).

  FIG. 2 is a functional block diagram for explaining a main part of the control function by the electronic control unit 90. In FIG. 2, the hybrid control means included in the HV_ECU, that is, the hybrid control unit 92 includes a function for controlling the drive of the engine 14 and a function for instructing the operation of the electric motor MG, and the engine 14 and the electric motor MG are controlled by these control functions. And control of the entire vehicle 10 including hybrid drive control that travels using the power as a driving force source. For example, the hybrid control unit 92 calculates a required drive torque Touttgt as a drive request amount (that is, a driver request amount) for the vehicle 10 by the driver based on the accelerator opening θacc and the vehicle speed V, and transmission loss, auxiliary load, In consideration of the gear ratio γ of the automatic transmission 18, the charging capacity SOC of the battery unit 68, and the like, the output torque of the driving power source (engine 14 and electric motor MG) for obtaining the required driving torque Touttgt is calculated. The hybrid control unit 92 controls the throttle valve opening, the fuel injection amount (fuel supply amount), the ignition timing, and the like so that the calculated output torque (engine torque) Te of the engine 14 is obtained. Se is output. Further, the hybrid control unit 92 outputs a command signal for controlling the electric motor MG to the electric motor control unit 94 to be described later so that the calculated output torque (MG torque) Tmg of the electric motor MG is obtained. The required drive amount includes, in addition to the required drive torque Touttgt [Nm] in the drive wheel 34, the required drive force [N] in the drive wheel 34, the required drive power [W] in the drive wheel 34, and the transmission output shaft 24. The required transmission output torque, the required transmission input torque at the transmission input shaft 36, and the like can also be used. Further, the accelerator opening degree θacc [%], the throttle valve opening degree, the intake air amount, or the like can also be used as the required drive amount.

  When the hybrid controller 92 performs motor traveling (EV traveling) using only the electric motor MG as a driving force source for traveling, the power between the engine 14 and the torque converter 16 is released by releasing the connection / disconnection clutch K0. The transmission path is cut off, and an MG torque Tmg necessary for EV traveling is output from the electric motor MG by an electric motor control unit 94 described later. On the other hand, the hybrid control unit 92 engages the connecting / disconnecting clutch K0 and engages the torque with the engine 14 when performing engine traveling that travels at least using the engine 14 as a driving power source for traveling, that is, hybrid traveling (EHV traveling). The power transmission path to the converter 16 is connected, and the engine control unit 94 outputs the MG torque Tmg as the assist torque from the motor MG as needed by the motor control unit 94 while outputting the engine torque Te necessary for EHV traveling to the engine 14. .

  The electric motor control unit 94 controls the inverter unit 54 and the like based on the command signal from the hybrid control unit 92 (that is, based on communication with the hybrid control unit 92) so as to obtain the necessary MG torque Tmg. The motor control command signal Sm to output is output to control the operation of the motor MG as a driving force source or a generator.

  The shift control unit 96 is based on, for example, a predetermined state (shift diagram, shift map; not shown) based on the vehicle state (for example, the actual vehicle speed V and the requested drive amount calculated by the hybrid control unit 92). Then, it is determined whether or not the shift of the automatic transmission 18 should be executed, and a hydraulic control command signal Sp (for example, a shift command value) for obtaining the determined gear stage (gear ratio) is output to the hydraulic control circuit 40. Thus, the automatic transmission control of the automatic transmission 18 is executed.

  Here, in the hybrid vehicle 10, although the driving force is required, the driving wheel 34 is fitted into a hole or a side groove on the road surface to stop rotating, and is mechanically connected to the driving wheel 34. The electric motor MG that is present may also stop rotating. Such a state is called a motor lock of the electric motor MG, and includes not only a complete stop of the rotation of the electric motor MG but also a state of extremely low speed rotation. In this motor lock, a relatively large current is continuously supplied to the specific phase coil of the electric motor MG and the specific phase current control element of the inverter, so that the current control of the specific phase coil and inverter of the electric motor MG is controlled. The device could be thermally damaged.

  The hybrid control unit 92 drives the electric motor MG in order to thermally protect the electric motor MG in the motor locked state that is forcibly stopped even though the driving force is required as described above. A motor lock determination unit 100, a temperature determination unit 102, and a lock-up clutch control unit 104 are provided so that the electric motor MG can be rotated and the heat protection is performed instead of reducing the current.

  For example, in the power-on motor running in which the electric motor MG is used as a drive source and the lockup clutch L / C is engaged, the motor lock determination unit 100 is configured such that, for example, a drive wheel is fitted into a depression or a side groove on a road surface. When the driving wheel to which the driving force is transmitted stops or enters a rotation stopped state that rotates slightly, or when riding on the curb or stopping on the uphill road, the driving force and the thrust in the downward direction due to the vehicle weight When the motor MG is balanced, the motor lock of the motor MG, which is in a rotation stop state even though the drive current is supplied to the motor MG, is changed to the actual accelerator opening θacc or the actual accelerator opening from a previously stored relationship. The required driving force Pq calculated based on θacc and the vehicle speed V is equal to or higher than a predetermined determination value A, and the rotation speed Nmg of the electric motor MG or the vehicle speed V is equal to or lower than the predetermined determination value B. To make a decision based on A relatively large drive current is supplied to the motor MG when the motor MG is stopped or at a very low rotation, so that a relatively large current is continuously supplied to the coil of a predetermined phase and the motor MG needs to be thermally protected. In order to determine such a motor lock state, the determination value A and the determination value B are experimentally obtained in advance.

  The temperature determination unit 102 determines whether or not the coil temperature Tmc of the electric motor MG exceeds a preset temperature determination value Tmc1, or the temperature Ti of the current control element of the inverter 54 exceeds a preset temperature determination value Ti1. Whether or not the electric motor MG or the inverter 54 needs to be thermally protected is determined based on whether or not the electric motor MG or the inverter 54 is in a necessary state.

  The lockup clutch control unit 104 determines that the motor lock determination unit 100 determines that the motor MG is locked, and the temperature determination unit 102 determines that the motor MG or the inverter 54 needs to be thermally protected. Then, the lock clutch L / C is brought into a slip or release state. Specifically, the slip amount is determined based on the temperature Tmc of the coil of the electric motor MG or the temperature Ti of the current control element of the inverter 54 from the relationship shown in FIG. 3 stored in advance, and locked so that the slip amount can be obtained. The engagement hydraulic pressure of the up clutch L / C is controlled. In the relationship of FIG. 3, when the temperature Tmc of the coil of the electric motor MG or the temperature Ti of the current control element of the inverter 54 is lower than the temperature judgment value Tmc1 or the temperature judgment value Ti1, no thermal protection is necessary, so no slip occurs. When it becomes equal to or higher than the determination value Tmc1 or the temperature determination value Ti1, the slip amount of the lockup clutch L / C is increased as the temperature rises, and finally the lockup clutch L / C is released.

  In addition, the lockup clutch control unit 104, for example, in the power-on motor running in which the electric motor MG is a driving source and the lockup clutch L / C is engaged, the temperature determination unit 102 determines the power performance of the electric motor MG. When it is determined that it is necessary to suppress the decrease, the lock-up clutch L / C is set to the slip or release state. Specifically, the slip amount is determined based on the temperature Tmc of the coil of the electric motor MG from the relationship shown in FIG. 3 stored in advance, and the engagement hydraulic pressure of the lockup clutch L / C is set so as to obtain the slip amount. Control.

  FIG. 4 is a flowchart for explaining a main part of the control operation of the hybrid control unit 92 of the electronic control unit 90, and is repeatedly executed with an extremely short cycle time of about several milliseconds to several tens of milliseconds, for example.

  4, in S1 corresponding to the motor lock determination unit 100, for example, in the power-on motor travel in which the electric motor MG is used as a drive source and the lock-up clutch L / C is engaged, the drive wheels 34 are formed on the road surface. The motor lock of the electric motor MG that is fitted in the side groove and stops its rotation or is in a stopped state such as extremely low rotation is that the accelerator opening θacc or the required driving force Pq calculated based thereon is equal to or greater than a predetermined determination value A And the rotational speed Nmg or the vehicle speed V of the electric motor MG is determined based on the predetermined determination value B or less. If the determination in S1 is negative, this routine is terminated. If the determination is positive, in S2, the coil temperature Tmc of the electric motor MG and the temperature Ti of the current control element of the inverter 54 are read.

  Next, in S3 corresponding to the temperature determination unit 102, whether or not the coil temperature Tmc of the electric motor MG has exceeded a preset temperature determination value Tmc1, or the temperature Ti of the current control element of the inverter 54 is set in advance. It is determined whether or not the temperature determination value Ti1 is exceeded. If the determination in S3 is negative, this routine is terminated. If the determination is affirmative, the motor MG or the inverter 54 needs to be thermally protected, so S4 corresponding to the lockup clutch control unit 104 is determined. Is executed.

  In S4, the lock-up clutch L / C is slipped or released, thereby allowing relative rotation on the input side and output side of the lock-up clutch L / C, regardless of the rotation stop state of the drive wheels 34. The electric motor MG is rotated. This eliminates the continuous flow of a large current through the coil of the specific phase of the motor and the current control element of the specific phase of the inverter. Therefore, the coil of the specific phase of the motor and the current control element of the specific phase of the inverter Is prevented from being thermally damaged. At the same time, the torque amplification effect of the torque converter 16 is obtained, so that the transmission torque to the drive wheels 34 is increased. For example, in S4, the slip amount is determined based on the temperature Tmc of the coil of the electric motor MG or the temperature Ti of the current control element of the inverter 54 from the relationship shown in FIG. 3 stored in advance, and the lock is made so that the slip amount is obtained. The engagement hydraulic pressure of the up clutch L / C is controlled. As shown in FIG. 3, as the coil temperature Tmc of the electric motor MG or the temperature Ti of the current control element of the inverter 54 is higher, the slip amount is larger than when the temperature is low.

  As described above, according to this embodiment, when the rotation stop state of the electric motor MG, that is, the motor lock is generated and it is determined, the lockup clutch L / C is released or slipped. For this reason, for example, when the driving wheel is fitted into a recess or a side groove on the road surface and the driving wheel to which the driving force is transmitted stops or rotates slightly, or the driving wheel is turned to the curb When the driving force is balanced with the thrust in the downward direction due to the vehicle weight when riding or when the hill is stopped, even if the driving wheel is in a stopped state even though the driving current is supplied to the motor MG, the motor Since the MG rotates, it is eliminated that a large current continues to flow through the specific phase coil of the electric motor MG or the specific phase current control element of the inverter 54. Therefore, the specific phase coil of the electric motor MG is eliminated. And the current control element of the specific phase of the inverter 54 is preferably prevented from being thermally damaged. At the same time, the torque amplifying function of the torque converter 16 can be obtained, and there is an advantage that the torque transmitted to the drive wheels 34 is increased.

  In addition, according to the present embodiment, the motor lock of the electric motor MG is generated and determined, and the coil temperature Tmc of the electric motor MG or the temperature Ti of the current control element of the inverter 54 that controls the electric current of the electric motor MG is previously determined. When the set high temperature determination value Tmc1 or Ti1 is exceeded, the lockup clutch L / C is released or slipped. For this reason, the lockup clutch L / C is engaged as much as possible when the vehicle is traveling, and the transmission efficiency of the driving force of the hybrid vehicle is enhanced.

  Further, according to this embodiment, the higher the coil temperature Tmc of the motor MG or the temperature Ti of the current control element of the inverter 54 that controls the current of the motor MG, the lower the lock-up clutch L / C. The slip amount is increased. As the coil temperature Tmc of the electric motor MG or the temperature Ti of the current control element of the inverter 54 that controls the electric current of the electric motor MG is higher, it is necessary to avoid the motor lock state. By doing so, the thermal protection of the electric motor MG is achieved. Is obtained appropriately.

  Further, according to the present embodiment, the motor lock of the electric motor MG is that the accelerator opening degree θacc or the required driving force calculated based on the accelerator opening degree θacc and the vehicle speed V is equal to or greater than a predetermined value and the rotational speed of the electric motor MG. It is determined when Nmg or the vehicle speed V is equal to or less than a predetermined value. For this reason, the motor lock of the electric motor MG requiring heat protection is accurately determined.

  As mentioned above, although the Example of this invention was described in detail based on drawing, this invention is applied also in another aspect.

  For example, in the above-described embodiment, as shown in FIG. 4, the motor lock of the motor MG is determined, and the coil temperature Tmc of the motor MG or the temperature Ti of the current control element of the inverter 54 that controls the current of the motor MG is determined. When it is determined that the preset high temperature determination value Tmc1 or Ti1 is exceeded, the lockup clutch L / C has been released or slipped, but immediately after the rotation stop state of the electric motor MG, that is, motor lock is determined. The lockup clutch L / C may be released or slipped.

  In the above-described embodiment, the clutch K0 is provided between the engine 14 and the electric motor MG. However, the clutch K0 is not necessarily provided, and the engine 14 and the electric motor MG may be directly connected. good.

  In the above-described embodiment, the first rotating element connected to the engine 14, the second rotating element connected to the differential control motor, and the motor MG are connected between the engine 14 and the electric motor MG. Further, an electric continuously variable transmission including a planetary gear device having a third rotating element may be inserted.

  The engine 14 described above is, for example, a gasoline engine that generates power by burning fuel, but may be a diesel engine or other internal combustion engine.

  In the above-described embodiment, the torque converter 16 with the lock-up clutch L / C is used as the fluid transmission, but other fluid couplings such as a fluid coupling with the lock-up clutch L / C having no torque amplifying action are used. A fluid transmission may be used.

  In the above-described embodiment, the vehicle 10 is provided with the automatic transmission 18. However, the vehicle 10 may be a continuously variable transmission having a forward / reverse switching mechanism or a parallel-shaft always-mesh transmission. .

  The above description is only an embodiment, and the present invention can be implemented in variously modified and improved forms based on the knowledge of those skilled in the art.

10: Vehicle 14: Engine 18: Automatic transmission 34: Drive wheel 90: Electronic control device (control device)
92: Hybrid control unit 100: Motor lock determination unit 102: Temperature determination unit 104: Lock-up clutch control unit MG: Electric motor

Claims (3)

A drive control device for a hybrid vehicle comprising a fluid transmission device with a lock-up clutch and a transmission between an engine and a motor as drive sources and drive wheels,
Determining a rotation stop state of the electric motor based on at least the rotational speed of the electric motor and the driving force of the electric motor;
The hybrid vehicle drive control device, wherein when the rotation stop state of the electric motor is determined, the lock-up clutch is released or slipped.   When it is determined that the motor has stopped rotating, and the coil temperature of the motor or the temperature of the inverter that controls the current of the motor exceeds a preset high temperature determination value, the lockup clutch is released or slipped. The drive control apparatus of the hybrid vehicle of Claim 1.   3. The hybrid vehicle drive according to claim 2, wherein the slip amount of the lockup clutch is increased as the coil temperature of the motor or the temperature of the inverter that controls the current of the motor is higher than when the temperature is lower. Control device.

Images